As You know: "Absolute Maximum Ratings DC Current per I/O Pin = 40mA". (Atmel, doc8161.pdf)
Next, on http://arduino.cc/en/Tutorial/Blink one can read:
"If you've got experience with electronics, you may notice that the LED doesn't have a resistor in series with it. This is because the amount of current coming out of the output pin of the Arduino is low enough that it won't damage the LED. "
So, I made some measurements (Arduino Uno, pin 8 and 9, AMPROBE 33XR-A):
little red LED = 70 mA, red power LED = 57 mA, white power LED = 68 mA
I tested my multimeter with 10k ohm and 220 ohm to verify it measures current flawless.
My question: is there really no need for current limiting resistor? Or is my multimeter fooling me?
Confusing about maximal current per Pin